Nitrogen and Oxygen Dual-Doped Carbon as High-Rate Long-Cycle-Life Anode Materials for Lithium-Ion Batteries

Defect-type carbon, doped with nitrogen and oxygen, is synthesized using the high-temperature solid-phase method. X-ray photoelectron spectroscopy analysis reveals the presence of nitrogen, including pyridine nitrogen, pyrrole nitrogen, and graphitized nitrogen, incorporated into the carbon structure. Additionally, oxygen is introduced into carbon, with both CO and CO functionalities are observed. Transmission electron microscopy and scanning electron microscopy indicate that all samples exhibit a morphology of carbon microblocks with localized turbocharged lattice regions. Electrochemical tests demonstrate that the nitrogen- and oxygen-doped carbon microblocks exhibit excellent cycling performance and high rate capacity. Specifically, at current densities of 1 and 2 A g⁻¹, the rate capacity remains at 385.6 and 214.4 mA h g⁻¹, respectively. Furthermore, the discharge capacity at 5 A g⁻¹ remains at 58.3 mA h g⁻¹ on the 3500th cycle. The defects introduced by nitrogen and oxygen doping not only enhance reactivity and electronic conductivity but also improve lithium-ion diffusion dynamics.